A conventional tree is pruner shown in FIGS. 9 and 10, and generally includes rod 81 with a fixed part 82 connected to a top thereof and the fixed part 82 includes an extension which has a fixed edge 821. An arm 84 has a first end pivotably connected to the fixed part 82 and a movable part 83 has one end connected to the arm 84. The mediate portion is pivotably connected to the fixed part 82 and the movable part 83 includes a movable edge 831. A spring 85 is connected between a second end of the arm 84 and the fixed part 82. A stationary pulley 87 is connected to the rod 81 and located close to the fixed part 82 and a movable pulley 86 is connected the second end of the arm 84. A rope 88 has one end fixed to the pulley frame for the movable pulley 86 and the other end of the rope 88 reeves the fixed pulley 87 and the movable pulley 86 so that the user can pull the second end of the rope 88 as shown in FIG. 13 to pivot the arm 84 relative to the fixed part 82 and the movable part 83 is pivoted so that the movable edge 831 moves toward the fixed edge 821 to cut branches between the fixed edge 821 and the movable edge 831.
The fixed pulley 87 is located close to the arm 84 so that when operating the tree pruner, the angle “θ” between the line connected between the fixed pulley 87 and the movable pulley 86 and the rope 88 in vertical direction changes a lot. This requires more force “Fa” to pull the rope 88 and is inconvenient for some users.
The present invention intends to provide a tree pruner wherein the angle between the line connected between the fixed pulley and the movable pulley and the rope in vertical direction changes a small angle when operating the pruner so that the user simply applies a small force to prune the branches of trees.